2009 Volume 25 Issue 2 Pages 307-310
The mesostructure of nanoparticle stabilized interfacial films, in systems such as particle stabilized emulsions, plays a key, yet little understood, role. We have studied a system of gold nanoparticles being formed and aggregating at a planar oil/water interface using optical microscopy. A rapid “nucleation” step of meso (micron) scale aggregates was observed. Aggregation of the meso aggregates to form a percolating structure is seen to switch from a slow to a fast aggregation regime. Aggregation in the slow regime appears to be reaction limited. We tentatively attribute the fast aggregation regime to a capillary attraction.